Add sql language docs (#32003)

Closes: https://github.com/zed-industries/zed/issues/9537

Pairs with removing `prettier-plugin-sql` from the sql extension:
- https://github.com/zed-extensions/sql/pull/19

Release Notes:

- N/A

docs/src/SUMMARY.md

@@ -126,6 +126,7 @@
 - [Scala](./languages/scala.md)
 - [Scheme](./languages/scheme.md)
 - [Shell Script](./languages/sh.md)
+- [SQL](./languages/sql.md)
 - [Svelte](./languages/svelte.md)
 - [Swift](./languages/swift.md)
 - [Tailwind CSS](./languages/tailwindcss.md)

docs/src/languages/sql.md

@@ -0,0 +1,68 @@
+# SQL
+
+SQL files are handled by the [SQL Extension](https://github.com/zed-extensions/sql).
+
+- Tree-sitter: [nervenes/tree-sitter-sql](https://github.com/nervenes/tree-sitter-sql)
+
+### Formatting
+
+Zed supports auto-formatting SQL using external tools like [`sql-formatter`](https://github.com/sql-formatter-org/sql-formatter).
+
+1. Install `sql-formatter`:
+
+```sh
+npm install -g sql-formatter
+```
+
+2. Ensure `shfmt` is available in your path and check the version:
+
+```sh
+which sql-formatter
+sql-formatter --version
+```
+
+3. Configure Zed to automatically format SQL with `sql-formatter`:
+
+```json
+  "languages": {
+    "SQL": {
+      "formatter": {
+        "external": {
+          "command": "sql-formatter",
+          "arguments": ["--language", "mysql"]
+        }
+      }
+    }
+  },
+```
+
+Substitute your preferred [SQL Dialect] for `mysql` above (`duckdb`, `hive`, `mariadb`, `postgresql`, `redshift`, `snowflake`, `sqlite`, `spark`, etc).
+
+You can add this to Zed project settings (`.zed/settings.json`) or via your Zed user settings (`~/.config/zed/settings.json`).
+
+### Advanced Formatting
+
+Sql-formatter also allows more precise control by providing [sql-formatter configuration options](https://github.com/sql-formatter-org/sql-formatter#configuration-options). To provide these, create a `sql-formatter.json` file in your project:
+
+```json
+{
+  "language": "postgresql",
+  "tabWidth": 2,
+  "keywordCase": "upper",
+  "linesBetweenQueries": 2
+}
+```
+
+When using a `sql-formatter.json` file you can use a more simplified set of Zed settings since the language need not be specified inline:
+
+```json
+  "languages": {
+    "SQL": {
+      "formatter": {
+        "external": {
+          "command": "sql-formatter"
+        }
+      }
+    }
+  },
+```